Multi-author Review

Cellular and Molecular Life Sciences CMLS

, Volume 61, Issue 21, pp 2695-2703

First online:

What’s new in the renin-angiotensin system?

Hijacking epidermal growth factor receptors by angiotensin II: new possibilities for understanding and treating cardiac hypertrophy
  • N. J. SmithAffiliated withDepartment of Pharmacology, University of Melbourne
  • , H. -W. ChanAffiliated withGene Transcription Laboratory and Molecular Endocrinology Laboratory, Baker Heart Research Institute
  • , J. E. OsborneAffiliated withGene Transcription Laboratory and Molecular Endocrinology Laboratory, Baker Heart Research Institute
  • , W. G. ThomasAffiliated withDepartment of Biochemistry and Molecular Biology, Monash University
  • , R. D. HannanAffiliated withDepartment of Biochemistry and Molecular Biology, University of MelbourneGrowth Control Laboratory, The Peter MacCallum Cancer Institute Email author 

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Abstract.

Activation of the type 1 angiotensin II receptor (AT1R) is associated with the aetiology of left ventricular hypertrophy, although the exact intracellular signalling mechanism(s) remain unclear. Transactivation of the epidermal growth factor receptor (EGFR) has emerged as a central mechanism by which the G protein-coupled AT1R, which lacks intrinsic tyrosine kinase activity, can stimulate the mitogen-activated protein kinase signalling pathways thought to mediate cardiac hypertrophy. Current studies support a model whereby AT1R-dependent transactivation of EGFRs on cardiomyocytes involves stimulation of membrane-bound metalloproteases, which in turn cleave EGFR ligands such as heparin-binding EGF from a plasma membrane-associated precursor. Numerous aspects of the ‘triple membrane-passing signalling’ paradigm of AT1R-induced EGFR transactivation remain to be characterised, including the identity of the specific metalloproteases involved, the intracellular mechanism for their activation and the exact EGFR subtypes required. Here we examine how ‘hijacking’ of the EGFR might explain the ability of the AT1R to elicit the temporally and qualitatively diverse responses characteristic of the hypertrophic phenotype, and discuss the ramifications of delineating these pathways for the development of new therapeutic strategies to combat cardiac hypertrophy.

Key words.

Type 1 angiotensin II receptor (AT1R) transactivation EGFR metalloprotease HB-EGF cardiac hypertrophy